1. Field of the Invention
A multi-layer substrate and an electronic device having the same consistent with the present general inventive concept relate to improving a return current path of a signal line.
2. Description of the Related Art
In general, a substrate is widely used as a component of an electronic device from a home appliance such as a digital TV, a computer, etc. to a high technology communicating device. The substrate forms a signal line on a predetermined main body to couple electrical components such as an integrated circuit, a resistor, a switch, etc., or signal lines, thereby electrically connecting or transmitting a signal.
The substrate is classified into a single side substrate, a double side substrate, a multi-layer substrate, etc., according to the number of layers, and a component mounting capacity becomes superior as the number of layers increases. The single surface substrate is employed for a product such as a radio, etc., a circuit of which is not complicated, and the multi-layer substrate is employed for various electronic devices such, as a high performance computer, etc.
In general, in the multi-layer substrate, a substrate main body and a layer are layered in sequence, and a via hole is formed in the substrate main body to connect signal lines provided in other layers.
Here, when a data communication, a power supplying, a signal having a predetermined frequency, etc., are transmitted through the signal line, a return current is generated in an opposite direction to a signal transmission direction. It is preferable that the length, the path, etc., of the return current correspond with to the length, the path, etc., of the signal transmission path.
However, in the conventional multi-layer substrate, a signal distortion is generated due to discontinuity of the return current, and noise is generated at the multi-layer substrate which increases an electromagnetic in reference (EMI), etc. Also, EMI is radiated in a radial direction of a via hole to have an effect on other signals, thereby reducing a signal transmitting ability.